Breath-hold Time Research Articles

Accelerated cardiac cine with spatio-coil regularized deep learning reconstruction.

To develop an iterative deep learning (DL) reconstruction with spatio-coil regularization and multichannel k-space data consistency for accelerated cine imaging. This study proposes a Spatio-Coil Regularized DL (SCR-DL) approach for iterative deep learning reconstruction incorporating multicoil information in data consistency and regularizer. SCR-DL uses shift-invariant convolutional kernels to interpolate missing k-space lines and reconstruct individual coil images, followed by a regularizer that operates simultaneously across spatial and coil dimensions using learned image priors. At 8-fold acceleration, SCR-DL was compared with Generalized Autocalibrating Partially Parallel Acquisition (GRAPPA), sensitivity encoding (SENSE)-based DL and spatio-temporal regularized (STR)-DL reconstruction. In the retrospective undersampled cine, images were quantitatively evaluated using normalized mean square error (NMSE) and structural similarity index measure (SSIM). Additionally, agreement for left-ventricular ejection fraction and left-ventricular mass were assessed using prospectively accelerated cine images at 2-fold and 8-fold accelerations. The SCR-DL algorithm successfully reconstructed highly accelerated cine images. SCR-DL had significant improvements in NMSE (0.03 ± 0.02) and SSIM (91.4% ± 2.7%) compared with GRAPPA (NMSE: 0.09 ± 0.04, SSIM: 69.9% ± 11.1%; p < 0.001), SENSE-DL (NMSE: 0.07 ± 0.04, SSIM: 86.9% ± 3.2%; p < 0.001), and STR-DL (NMSE: 0.04 ± 0.03, SSIM: 90.0% ± 2.5%; p < 0.001) with retrospective undersampled cine. Despite the 3-fold reduction in scan time, there was no difference between left-ventricular ejection fraction (59.8 ± 4.5 vs. 60.8 ± 4.8, p = 0.46) or left-ventricular mass (73.6 ± 19.4 g vs. 73.2 ± 19.7 g, p = 0.95) between R = 2 and R = 8 prospectively accelerated cine images. SCR-DL enabled highly accelerated cardiac cine imaging, significantly reducing breath-hold time. Compared with GRAPPA or SENSE-DL, images reconstructed with SCR-DL showed superior NMSE and SSIM.

Physiological Challenges and Adaptations in Competitive Freediving

Competitive freediving is associated with extreme physiologic challenges due to the effects of apnea, submersion in water, and increased ambient pressure. There has nevertheless been a continued progression of world records across freediving disciplines in recent years, with breath-hold times exceeding 10 minutes, and reaching diving depths beyond 200 meters of seawater. The main physiological determinants of breath-hold endurance are the available oxygen stores, i.e., intrapulmonary gas volume, inspired gas concentration, and rate of oxygen consumption. Other factors such as psychological and inherent factors contribute to the individual tolerance to an increasing respiratory stimulus with prolonged breath-hold duration. A freediving athlete must be able to tolerate apnea to stay underwater long enough to reach great distance or depth and resurface safely. Elite freedivers exhibit somewhat remarkable physiological adaptations such as a more pronounced diving-response and hypercapnia tolerance compared to non-divers, as well as metabolic and cerebrovascular adaptations. To reach great depths, elite freedivers employ a breathing technique called glossophyryngeal insufflation (GI) that is enlarging the ratio of total lung capacity to residual volume, thus, mitigating risk of lung squeeze and increasing intrapulmonary gas volume, and thereby enhancing available oxygen stores. Pulmonary anatomy and physiology could not be accounted to restrict the breath-hold diving depths achieved by competitive athletes. However, the acutely increased intrapulmonary pressure during GI is transmitted to the pulmonary vasculature, thereby eliciting a right ventricular pressure overload, and left ventricular dysfunction that may augment hypotension and syncope during glossopharyngeal insufflation. Due to extreme diffusion gradients between alveolar pN2 and N2 pressures in the body tissues at great depth, N2 will be forced into blood and body tissues during descent, elevating risk of N2 narcosis and decompression illness during deep dives. Breath-hold training and preparation have been shown to enhance breath-hold performance. This review highlights recent data on the profound cardiovascular, respiratory, and gas exchange effects that are observed in competitive freedivers, and discusses possible adaptations and risks for humans.

Adverse Events in Competitive Freediving – Clinical Presentation, Management, and Prevention

Freediving (synonyms: breath-hold diving, apnea diving) has become a popular leisure activity and continues to gain popularity and recognition as both a competitive and recreational sport. Formal freediving competitions are sanctioned by the international Confédération Mondiale des Activités Subaquatiques (CMAS) or the Association Internationale pour le Développement de l’Apnée (AIDA). Both organizations have set up rules and guidelines for competitive pool disciplines where athletes compete for maximum submerged breath-hold time or underwater swimming distance with or without fins. In freshwater disciplines athletes strive for maximum depth using different freediving techniques. These aquatic breath-holding activities carry unique medical risks that are related to environmental factors eliciting extreme physiological challenges. Pool disciplines carry an increased risk of hypoxemia and, consequently, loss of consciousness, particularly in untrained individuals. Hypoxic complications are reported to occur in up to 10% of dives during freediving competitions. Shallow water blackout following hyperventilation to extend breath-hold capability is a serious risk applying to all aquatic breath-hold activities, however, is more common during recreational freediving. Deep freediving poses the athlete to further risks such as barotrauma of ear drums or lungs, immersion pulmonary edema, nitrogen narcosis, and decompression sickness when reaching great depths. While serious complications in competitive freediving are rare, however, the risk clearly rises with increasing depth. Special breathing techniques to increase lung volumes such as glossopharyngeal insufflation carry additional risks. This article reviews possible complications and injury that may occur in competitive freedivers and discusses strategies for management and prevention of possible injury.

Impact of glossopharyngeal insufflation and complete exhalation on breath-hold performance and physiological parameters in elite skin divers.

This study examined the physiological responses of ten elite divers to normal breathing (BHn), glossopharyngeal inhalation (BHi), and complete exhalation (BHe) prior to five maximal breath-hold (BH) efforts. Breath-hold time (BHT), hemological variables, mean arterial pressure (MAP), other hemodynamic indices, and diaphragmatic activity (DA) were recorded. During BHs, phases were identified as easy-going (EPh: minimal DA), struggling (SPh: increased DA), PhI (MAP transition), PhII (MAP stabilization), and PhIII (steep MAP increase). BHi significantly extended BHT (309.14 ± 12.91s) compared to BHn (288.77 ± 10.99s) and BHe (151.18 ± 10.94s) (P = 0.001). BHT, EPh, and SPh in BHi increased by 7.05%, 2.57%, and 11.08% over BHn, respectively. PhIII appeared earlier in BHe than in other conditions (P < 0.001) and accounted for 47.07%, 44.96%, and 60.18% of BHT in BHn, BHi, and BHe, respectively. SPh comprised 47.10%, 46.01%, and 45.13% of BHT in BHn, BHi, and BHe, respectively, with SPh onset coinciding with PhIII onset in BHn and BHi but not in BHe. Bradycardia was more pronounced in BHe, maintaining better stroke volume. No significant differences in red blood cells or maximal MAP were noted across conditions. Glossopharyngeal inhalation improves BHT and extends EPh and SPh durations. PhIII onset is linked to SPh in BHn and BHi but not in BHe. BHe triggers an earlier MAP rise, leading to stronger parasympathetic responses. Despite similar maximal MAP across conditions, the higher BHT and tissue hypoxemia in BHi and BHn suggest MAP is a key limiting factor in apnoea.

Deep Learning Reconstruction of Prospectively Accelerated MRI of the Pancreas: Clinical Evaluation of Shortened Breath-Hold Examinations With Dixon Fat Suppression.

Deep learning (DL)-enabled magnetic resonance imaging (MRI) reconstructions can enable shortening of breath-hold examinations and improve image quality by reducing motion artifacts. Prospective studies with DL reconstructions of accelerated MRI of the upper abdomen in the context of pancreatic pathologies are lacking. In a clinical setting, the purpose of this study is to investigate the performance of a novel DL-based reconstruction algorithm in T1-weighted volumetric interpolated breath-hold examinations with partial Fourier sampling and Dixon fat suppression (hereafter, VIBE-DixonDL). The objective is to analyze its impact on acquisition time, image sharpness and quality, diagnostic confidence, pancreatic lesion conspicuity, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). This prospective single-center study included participants with various pancreatic pathologies who gave written consent from January 2023 to September 2023. During the same session, each participant underwent 2 MRI acquisitions using a 1.5 T scanner: conventional precontrast and postcontrast T1-weighted VIBE acquisitions with Dixon fat suppression (VIBE-Dixon, reference standard) using 4-fold parallel imaging acceleration and 6-fold accelerated VIBE-Dixon acquisitions with partial Fourier sampling utilizing a novel DL reconstruction tailored to the acquisition. A qualitative image analysis was performed by 4 readers. Acquisition time, image sharpness, overall image quality, image noise and artifacts, diagnostic confidence, as well as pancreatic lesion conspicuity and size were compared. Furthermore, a quantitative analysis of SNR and CNR was performed. Thirty-two participants were evaluated (mean age ± SD, 62 ± 19 years; 20 men). The VIBE-DixonDL method enabled up to 52% reduction in average breath-hold time (7 seconds for VIBE-DixonDL vs 15 seconds for VIBE-Dixon, P < 0.001). A significant improvement of image sharpness, overall image quality, diagnostic confidence, and pancreatic lesion conspicuity was observed in the images recorded using VIBE-DixonDL (P < 0.001). Furthermore, a significant reduction of image noise and motion artifacts was noted in the images recorded using the VIBE-DixonDL technique (P < 0.001). In addition, for all readers, there was no evidence of a difference in lesion size measurement between VIBE-Dixon and VIBE-DixonDL. Interreader agreement between VIBE-Dixon and VIBE-DixonDL regarding lesion size was excellent (intraclass correlation coefficient, >90). Finally, a statistically significant increase of pancreatic SNR in VIBE-DIXONDL was observed in both the precontrast (P = 0.025) and postcontrast images (P < 0.001). Also, an increase of splenic SNR in VIBE-DIXONDL was observed in both the precontrast and postcontrast images, but only reaching statistical significance in the postcontrast images (P = 0.34 and P = 0.003, respectively). Similarly, an increase of pancreas CNR in VIBE-DIXONDL was observed in both the precontrast and postcontrast images, but only reaching statistical significance in the postcontrast images (P = 0.557 and P = 0.026, respectively). The prospectively accelerated, DL-enhanced VIBE with Dixon fat suppression was clinically feasible. It enabled a 52% reduction in breath-hold time and provided superior image quality, diagnostic confidence, and pancreatic lesion conspicuity. This technique might be especially useful for patients with limited breath-hold capacity.

The harmful effects of smoking and factors affecting smoking: maximal voluntary breath-holding time and exercise capacity

Aim: The harmful effects of smoking and its impact on respiratory functions and exercise capacity are well-recognized health concerns in the present day, demanding further investigation. This study aims to assess the association between smoking and respiratory functions and exercise capacity while exploring factors contributing to smoking addiction. Methods: A total of 893 volunteers (mean age: 27.24 years, range: 17-67) participated in this study, with 77% having a university education and 58% being female. Participants were categorized into active smokers, passive smokers, and non-smokers. Maximum Voluntary Breath-holding Time , 6-minute walk test distance, and 30-second chair stand test were used to assess respiratory functions and exercise capacity. Participants provided information about their smoking habits, which was analyzed and reported. Results: There were no statistically significant differences in Maximum Voluntary Breath-holding Time, 6-minute walk test distance, and 30-second chair stand test scores between the groups (p&gt;0.05). However, all smokers exhibited psychological dependence on cigarettes, with 88% showing signs of physical dependence. Smoking initiation was significantly influenced by friends (64%). While 61% of active smokers acknowledged potential health issues associated with smoking, only 92% had not sought medical advice to quit smoking. Conclusion: This study did not demonstrate a conclusive effect of cigarette consumption on respiratory functions and exercise capacity. However, it revealed a strong association between smoking habits and social factors such as friendships. Additionally, most smokers exhibited psychological and physical dependence on cigarettes, emphasizing the need for further research and awareness campaigns to highlight the detrimental consequences of smoking.

The Course of Recovery From Moderate and Severe COVID-19 and its Sequelae: A Three-month Observational Follow-up Study in Indian Population

Introduction: Challenges associated with COVID-19 are not only associated with its acute phase but also with its sequelae. Multiple studies have been conducted on long-term follow ups of patients suffering from COVID-19. In a detailed search of the literature, we did not find any long-term follow up study in the Indian population. Methodology: The present study is an ambi-directional observational follow up study. A total of 83 patients were included in the study and a follow up was conducted at 2, 6 and 12 weeks after recovery from acute phase of moderate to severe COVID-19. The primary objective was to identify symptoms pertaining to respiratory, cardiac, neurological and mental health in post-COVID period. Secondary objectives were to identify patients consistent with a diagnosis of post-COVID syndrome and to assess the difference in the recovery profile between moderate and severe cases. Results: Significant improvement was observed in fatigue, cough, SpO2, breath-holding time and EuroQL-5D with maximum improvement by 12 weeks of recovery. Patients having longer ICU stays and requiring non-invasive ventilation had a longer persistence of symptoms. Forty-five patients had symptoms persistent even after 12 weeks consistent with a diagnosis of post-COVID syndrome. Conclusion: We observed 50% of the patients in the cohort had complete resolution of symptoms by six weeks follow up. Therefore, a follow up period of at least six weeks is warranted for all patients suffering from moderate to severe COVID-19, along with continuous screening of patients who tend to develop post-COVID-19 syndrome.

Effect of Pranayama on Breath Holding Time of College Students

Context: Pranayama is a method for regulating and manipulating breath and meditation. It enables individuals to achieve a state of profound relaxation while maintaining mental alertness. Recent research on the effects of yoga on the respiratory system over the long term has shown promising results. Aim: This study's primary objective was to assess pranayama's impact on breath holding time. Settings and Design The present investigation entail the examination of a group of 25 male participants who exhibited good health and fell within the age range of 21 to 26 years. Methods and Material: The participants who met the specified inclusion and exclusion criteria were subjected to a 15-minute pranayama session facilitated by a yoga instructor over a period of 12 weeks. Respiratory functioning before and after yoga was assessed using measurements of breath-holding duration. The parameters were analyzed using the student t-test. Results: The breath-holding duration have shown a notable increase compared to the period before engaging in yoga practice. Conclusions: The findings of this study demonstrate the positive impacts of consistent engagement in pranayama on respiratory functioning.

Assessing the effectiveness of inhalation therapy in patients with chronic airway diseases: A new digital measurement

BackgroundThis study aimed to evaluate the effectiveness of inhalation therapy in patients with chronic airway diseases via the use of a new multiparametric inhalation assessment device. MethodsA multiparametric inhalation evaluation device (PF810, UBREATH, Zhejiang, China) that could simulate common inhalation devices with 6 different levels (0-V) of resistance was used in this study. The device was considered suitable if the three parameters of peak inspiratory flow rate (PIFR), effective inspiratory time (EIT), and breath-hold time (BHT) after inspiration met the minimum requirements. ResultsA total of 4,559 tests were performed. The qualification rates of 0-V resistance gear from low to high were 3.38 % (I), 8.42 % (0), 15.31 % (II), 16.71 % (III), 20.27 % (IV), and 46.91 % (V). The COPD patients in the 3 experimental groups had the lowest percentages of isolates classified as resistant 0, III, and V, which were 5.65 %, 11.93 %, and 40.43 %, respectively. The lowest percentage was 39.67 % (V) for insufficient EIT and 18.40 % (V) for BHT less than 5 s after inspiration. The results of 149 subjects who had used the inhalation device showed that the VIE and EIT at 0 levels were significantly greater than those before training (Z= -5.651, -5.646, P < 0.001). The VIE and EIT at I-III and V significantly increased after training (all P < 0.05). ConclusionsPatients using portable inhaler devices do not always inhale with adequate flow patterns. The multiparametric inhalation assessment device may be useful in outpatient settings.

Effect of Buteyko Breathing Technique as an Adjunct to Routine Physiotherapy on Pulmonary Functions in Patients Undergoing Off-pump Coronary Artery Bypass Surgery: A Randomized Controlled Trial.

Coronary artery disease (CAD) poses a substantial and increasing public health concern in India, particularly among individuals aged 20 and above. The postoperative phase following coronary artery bypass graft (CABG) surgery presents potential complications, notably impacting the pulmonary system. Emerging evidence suggests that the Buteyko breathing technique not only improves lung function but also positively influences the psychological well-being of CABG patients. This study seeks to assess the impact of the Buteyko breathing technique on pulmonary functions in individuals who have undergone off-pump CABG. In this randomized controlled trial, patients undergoing off-pump CABG were allocated to either the Buteyko breathing technique group (n = 35) or the control group (n = 35). The intervention group received supervised Buteyko breathing technique sessions twice daily for 15 minutes, concurrently with cardiac rehabilitation from postoperative day (POD-2 to POD-7). The control group underwent phase I cardiac rehabilitation. Outcome measures, including pulmonary function test (PFT), chest expansion, and breath-holding tests were evaluated at baseline (POD-2) and conclusion (POD-7). Statistical analyses were conducted with a significance level set at p < 0.05. Both the control and intervention groups exhibited statistically significant improvements in pulmonary function, chest expansion at three levels, and breath-holding time (p = 0.0001). However, the Buteyko breathing group demonstrated a more significant improvement compared with the control group. The integration of the Buteyko breathing technique into conventional physiotherapy proves to be a beneficial strategy, leading to improvements in pulmonary function, breath-holding duration, and chest expansion for individuals who underwent off-pump CABG surgery. Mavkar SS, Shukla MP. Effect of Buteyko Breathing Technique as an Adjunct to Routine Physiotherapy on Pulmonary Functions in Patients Undergoing Off-pump Coronary Artery Bypass Surgery: A Randomized Controlled Trial. Indian J Crit Care Med 2024;28(3):280-285.TRI Number: CTRI/2022/12/048295.

Interrelations of physical state parameters and biological age of students in the process of physical education

Background and Study Aim. The objective of the study is to investigate the relationships of students' biological age (BA) with the parameters of functional and physical fitness (PF) in the process of adaptation to standard (university) and experimental physical education programs. Material and Methods. The studies were conducted at the National University of Telecommunications of Ukraine and involved 140 students aged 17-18 years old, comprising 80 boys and 60 girls. We recorded 55 indices of students' functional state and physical fitness, and determined their Body Mass Index (BMI). The experimental data were processed using methods of correlation, dispersion, and regression analysis. Mathematical models describing the relationships between BMI and key indicators of students' physical well-being were developed. Results. The impact of the program on 17-18-year-old students is marked by a decrease in BMI, an increase in the levels of physical fitness and overall well-being among both the experimental group of girls and boys. Additionally, there is a reduced correlation between BMI and the parameters of their physical health. The key indices of functional state and physical fitness determining the BMI of male and female students were identified. Multiple regression models were developed to illustrate the dependence of male and female BMI on somatic and functional indices. Quantitative characteristics of the degree of partial and total impact of key indices on male and female BMI were provided. It was found that the key indicators of students' physical state (PS) structure, which exerted the most significant influence on BMI, differ between young men and women. In young men, the key indicators influencing BMI include the following: Vital capacity (VC) accounts for 51.9% of BMI variation; self-perceived health status (SPHS) contributes 15.3%; static balancing (SB) affects 8.5%; inspiration breath-hold time (IBH) influences 8.4%; expiration breath-hold time (EBH) has a 0.8% impact; systolic blood pressure (SBP) plays a role with 4.6%; the number of sit-ups in 30 seconds (SU30s) is associated with 0.9%; and left hand muscle strength has a 0.6% influence. In girls, the key indicators are VC (34.5% of BMI variation), SBP (23.1%), and SB (7.9%). Conclusions. The experimental program of increased motor activity leads to an increase in the functional and motor capabilities of students, while simultaneously decreasing their BMI. Among the parameters studied, changes in vegetative parameters have the greatest impact on reducing students' BMI during the annual cycle of long-term adaptation to physical loads. In contrast, changes in somatic parameters and physical fitness parameters have a lesser influence on students' BMI. The calculated equations of multiple regression serve as model characteristics that reflect the relationships between BMI and the key indicators of functional state and physical fitness in 17-18-year-old students. These equations can be utilized to estimate, model, and predict the BMI of 17-18-year-old students of different genders when altering the parameters of their physical state in various conditions of daily life and activity.

Intra-patient and inter-observer image quality analysis in liver MRI study with gadoxetic acid using two different multi-arterial phase techniques.

To evaluate intra-patient and interobserver agreement in patients who underwent liver MRI with gadoxetic acid using two different multi-arterial phase (AP) techniques. A total of 154 prospectively enrolled patients underwent clinical gadoxetic acid-enhanced liver MRI twice within 12 months, using two different multi-arterial algorithms: CAIPIRINHA-VIBE and TWIST-VIBE. For every patient, breath-holding time, body mass index, sex, age were recorded. The phase without contrast media and the APs were independently evaluated by two radiologists who quantified Gibbs artefacts, noise, respiratory motion artefacts, and general image quality. Presence or absence of Gibbs artefacts and noise was compared by the McNemar's test. Respiratory motion artefacts and image quality scores were compared using Wilcoxon signed rank test. Interobserver agreement was assessed by Cohen kappa statistics. Compared with TWIST-VIBE, CAIPIRINHA-VIBE images had better scores for every parameter except higher noise score. Triple APs were always acquired with TWIST-VIBE but failed in 37% using CAIPIRINHA-VIBE: 11% have only one AP, 26% have two. Breath-holding time was the only parameter that influenced the success of multi-arterial techniques. TWIST-VIBE images had worst score for Gibbs and respiratory motion artefacts but lower noise score. CAIPIRINHA-VIBE images were always diagnostic, but with a failure of triple-AP in 37%. TWIST-VIBE was successful in obtaining three APs in all patients. Breath-holding time is the only parameter which can influence the preliminary choice between CAIPIRINHA-VIBE and TWIST-VIBE algorithm. If the patient is expected to perform good breath-holds, TWIST-VIBE is preferable; otherwise, CAIPIRINHA-VIBE is more appropriate.

Динамика физиологических показателей студентов г. Луганска при прохождении практики в высокогорье

Adverse ecological conditions put a strain on the functional reserves of young people. Hypoxic training in the mountains is the gold standard of adaptive physiology. The purpose of this paper was to study the physiological parameters of young Lugansk residents moving from the lowlands to the highlands. Materials and methods. Students of Lugansk State Pedagogical University (n = 19) were examined before, during and after their stay in the Elbrus region. To monitor the physiological parameters, pulse oximetry was performed using the MD300M device, blood pressure was measured using the auscultation method, Kérdö index and CO2 concentration in the blood using capnometry were determined. Results. The baseline level of health in students was found to be low. After a 5-day stay in the mountains, a certain increase in physiological well-being was noted, which persisted upon returning to Lugansk (aftereffect period). Namely, heart rate (HR) decreased from 86.14 ± 3.63 to 81.16 ± 2.19 bpm; 10 days later the effect remained: HR was 80.87 ± 4.77 bpm. Oxygen saturation increased from 94.86 ± 0.31 to 96.16 ± 0.32 %; on the 10th day upon returning to the city, it was 95.29 ± 0.33 %. Autonomic balance shifted from sympathicotonia (Kérdö index = 22.92 ± 5.48 conventional units) towards normotonia (Kérdö index = 15.56 ± 3.55 conventional units). CO2 concentration in the arterial blood was 4.73 ± 0.08 % at baseline, 5.03 ± 0.15 % on the 3rd day in the mountains, 5.16 ± 0.20 % on the 2nd day of aftereffect, and 4.86 ± 0.09 % on the 10th day. Breath-holding time increased, which indicates that adaptation to hypoxia occurred. During their stay in the mountains, students went on daily hikes at 1500– 3450 m above sea level. The fluctuating mode of hypoxic training was accompanied by a subjective feeling of unwellness, weakness and vertigo, which is understandable considering the mechanisms of physiological adaptation to hypoxia. The results of the study confirm that measures need to be taken in order to increase the level of functional reserves of young people living in Lugansk.

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method.

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure pulmonary alveolar-capillary reserve in both healthy and patient populations. The measurement provides an estimate of the participant's ability to recruit and distend pulmonary capillaries. The method has recently been reported to exhibit a high test-retest reliability in healthy volunteers during exercise of light to moderate intensity. Of note, this technique permits up to 12 repeated maneuvers and only requires a single breath with a relatively short breath-hold time of 5 s. Representative data are provided showing the gradual changes in DL,NO and DL,CO from rest to exercise at increasing intensitiesof up to 60% of maximal workload. The measurement of diffusing capacity and evaluation of alveolar-capillary reserve is a useful tool to evaluate the lung's ability to respond to exercise both in the healthy population as well as in patient populations such as those with chronic lung disease.

Compressed sensing with deep learning reconstruction: Improving capability of gadolinium-EOB-enhanced 3D T1WI

PurposeThe purpose of this study was to determine the utility of compressed sensing (CS) with deep learning reconstruction (DLR) for improving spatial resolution, image quality and focal liver lesion detection on high-resolution contrast-enhanced T1-weighted imaging (HR-CE-T1WI) obtained by CS with DLR as compared with conventional CE-T1WI with parallel imaging (PI). MethodsSeventy-seven participants with focal liver lesions underwent conventional CE-T1WI with PI and HR-CE-T1WI, surgical resection, transarterial chemoembolization, and radiofrequency ablation, followed by histopathological or >2-year follow-up examinations in our hospital. Signal-to-noise ratios (SNRs) of liver, spleen and kidney were calculated for each patient, after which each SNR was compared by means of paired t-test. To compare focal lesion detection capabilities of the two methods, a 5-point visual scoring system was adopted for a per lesion basis analysis. Jackknife free-response receiver operating characteristic (JAFROC) analysis was then performed, while sensitivity and false positive rates (/data set) for consensus assessment of the two methods were also compared by using McNemar's test or the signed rank test. ResultsEach SNR of HR-CE-T1WI was significantly higher than that of conventional CE-T1WI with PI (p < 0.05). Sensitivities for consensus assessment showed that HR-CE-MRI had significantly higher sensitivity than conventional CE-T1WI with PI (p = 0.004). Moreover, there were significantly fewer FP/cases for HR-CE-T1WI than for conventional CE-T1WI with PI (p = 0.04). ConclusionCS with DLR are useful for improving spatial resolution, image quality and focal liver lesion detection capability of Gd-EOB-DTPA enhanced 3D T1WI without any need for longer breath-holding time.

Feasibility of Breath-Hold Zero TE Magnetic Resonance Imaging Sequence for Evaluation of Pulmonary Arteriovenous Malformations After Embolotherapy.

We obtained breath-hold zero TE (ZTE) magnetic resonance imaging for the evaluation of pulmonary arteriovenous malformations before and after embolotherapy. To the best of our knowledge, there have been no reports of ZTE for the entire lung imaging in single breath-hold scan time such as 20 seconds. Breath-hold ZTE magnetic resonance imaging can be a useful technique for magnetic resonance-based follow-up of vascular lung diseases without using contrast media, reducing the undesired artifacts from metallic devices.

Chinese expert consensus on standardized inhaler device application in stable chronic airway diseases (2023)

Chinese expert consensus on standardized inhaler device application in stable chronic airway diseases (2023)

Effects of pelvic floor myofascial manipulation intervention on primiparas and neonates during the second stage of vaginal delivery.

A prolonged second stage of vaginal delivery increases the risk of shoulder dystocia, unnecessary episiotomies and cesarean sections. However, no standardized method has been proposed to tackle this issue. The effects of pelvic floor myofascial manipulation intervention during the second stage of labor in primiparas and its prognostic value in neonatal postpartum outcomes remain unknown. In the present study, a total of 60 primiparas who were expecting a vaginal delivery in the Second Affiliated Hospital of Hainan Medical College (Haikou, China) between October 2021 and January 2022 were selected. These women were randomly assigned to a control group (standard intrapartum care) or an experimental group (pelvic floor myofascial manipulation for 15-20 min during the second stage of labor along with standard intrapartum care) using a random number table, with 28 patients in each group. There was no significant difference in age, gestational time or body mass index between the two groups before delivery, indicating that the baseline data were comparable. The second stage of labor duration, forced breath-holding time and postpartum hemorrhage volume in the experimental group were significantly lower than those in the control group. The pain visual analog scale scores, fatigue scores and neonatal Apgar scores in the experimental group were also significantly lower than those in the control group. The rate of episiotomy in the experimental group was lower than that in the control group, but the difference was not statistically significant. In conclusion, pelvic floor myofascial manipulation intervention during the second stage of labor for primiparas with vaginal delivery can reduce the duration of the second stage of labor, the amount of bleeding during labor and the pain during labor. Meanwhile, it has the potential to improve neonatal outcomes.

Physiological Responses during Prolonged Immersed Static Apnea in Well-Trained Apneists

Breath-hold diving has been traditionally practiced for professional and recreational reasons and has recently emerged as a competitive sport. The physiological response during breath-holding, also known as diving response, consists mainly of bradycardia and peripheral vasoconstriction. Elite apneists can suppress the urge to breathe, sustain greater arterial desaturation and develop pronounced bradycardia, thus accomplishing impressively long breath-hold times. This study explored physiological responses during static apnea and their association with apnea duration in breath-hold divers with high physiological adaptations acquired from long-term apnea training. Nine well-trained competitive divers held their breath for as long as possible while floating motionlessly in a swimming pool (26–27 °C), simulating an actual “static apnea competition”. Long apnea durations (302 ± 60 s) as well as severe oxygen desaturation (minSaO2 46 ± 11%) and bradycardia (minHR 49 ± 8 bpm) were achieved. Apnea duration was positively correlated with forced vital capacity (r = 0.771) and apnea duration until initiation of desaturation (r = 0.736) and negatively correlated with minSaO2 (r = −0.672) (p &lt; 0.05). Moreover, minHR during apnea was correlated with pre-apneic hemoglobin concentration (r = 0.685) (p &lt; 0.05). The prolonged apnea durations achieved by the well-trained divers in this study, while performing maximum immersed static apnea under competitive simulated conditions, were related to their high lung volumes and their delayed and profound O2 desaturation, whereas their bradycardic response was not a decisive factor.

Physiological responses during static apnoea efforts in elite and novice breath-hold divers before and after two weeks of dry apnoea training

This study examined the effect of breath-hold (BH) training on apnoeic performance in novice BH divers (NBH:n = 10) and compared them with data from elite BH divers (EBH:n = 11). Both groups performed 5-maximal BHs (PRE). The NBH group repeated this protocol after two weeks of BH training (POST). The NBH group during BH efforts significantly increased red blood cell concentration (4.56 ± 0.16Mio/μl) by 5.06%, hemoglobin oxygen saturation steady state duration (110.32 ± 29.84 s) by 15.48%, and breath-hold time (BHT:144.19 ± 47.35 s) by 33.77%, primarily due to a 59.70% increase in struggle phase (71.85 ± 30.89 s), in POST. EBH group exhibited longer BHT (283.95 ± 36.93 s) and struggle-phase (150.10 ± 34.69 s) than NBH (POST). Elite divers recorded a higher peak MAP (153.18 ± 12.28 mmHg) compared to novices (PRE:123.70 ± 15.65 mmHg, POST:128.30 ± 19.16 mmHg), suggesting that a higher peak MAP is associated with a better BHT. The concurrent abrupt increase of diaphragmatic activity and MAP, seen only in the EBH group, suggests a potential interaction. Additionally, apnoea training increases red blood cells concentration in repeated apnoea efforts and increases BH stamina.